If you can think carefully than Microsoft is forcing all the users to switch to windows 10, who want to use MS office 2019. Other than this that is for windows 8.1 or older, it will not work. You have to consider one thing, that is MS office 2019 key works on windows 10 only. You can download it and use it without any worries - no fatal errors like the beta version. After a series of different versions, Microsoft comes up with a new Microsoft office 2019 product key.